I'm considering replacing the batteries in my recently-purchased 1989 Hunter 30. I understand that mixing battery types is not advisable, but does that mean that both battery banks should have the same type of batteries, or just the batteries *within* a bank should be the same type? Right now, the boat has 2 banks: Bank 1 is two 12V deep cycles in parallel and Bank 2 is two 6V Golf cart batteries in series. The golf cart batteries still seem okay, but the deep cycles seem to be nearing the end of their useful life. I have access to shore power now, but soon will not. As such, I'm thinking about Gel or AGM batteries as replacements....would I have to replace all four batteries (both banks), or could I just replace bank 1 (deep cycles) and keep the golf cart batteries? Any advice would be greatly appreciated. Thanks in advance. Sorry for the long post. Roger
1st time boat owner needs battery advice
- Thread starter parrothead531
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Its the charger voltage
Different types of batteries require different voltages when being recharged. That is why the all need to be the same unless you use different chargers for the different banks.
Different types of batteries require different voltages when being recharged. That is why the all need to be the same unless you use different chargers for the different banks.
you can mix IF
the battery types use the same charge voltage. Otherwise you will need a charger for each bank. Some AGMs use the same voltage as flooded batteries. Concorde AGMs say to charge at the same voltage as flooded batteries. The real problem with mixing different types and different ages of batteries is when they are in parallel when they are sitting idle or being discharged lightly. The weakest battery in the parallel string(s) will rob power from the stronger ones. If you keep the two banks separated with a switches and only use one bank at a time this would be ok. there are chargers that are designed to charge 2 separate banks of batteries, but at the same voltage. A battery combiner would also work to charge from a single charger. I would not mix gels with flooded batteries because gels need a lower bulk charge voltage. If you are going to be away from shore power and will be charging off the engine or solar, I would think about making them all the same type and age. It simplifies everything. There is a ton of discussions about this in the archives, probably more than you would be able to read in one night.
the battery types use the same charge voltage. Otherwise you will need a charger for each bank. Some AGMs use the same voltage as flooded batteries. Concorde AGMs say to charge at the same voltage as flooded batteries. The real problem with mixing different types and different ages of batteries is when they are in parallel when they are sitting idle or being discharged lightly. The weakest battery in the parallel string(s) will rob power from the stronger ones. If you keep the two banks separated with a switches and only use one bank at a time this would be ok. there are chargers that are designed to charge 2 separate banks of batteries, but at the same voltage. A battery combiner would also work to charge from a single charger. I would not mix gels with flooded batteries because gels need a lower bulk charge voltage. If you are going to be away from shore power and will be charging off the engine or solar, I would think about making them all the same type and age. It simplifies everything. There is a ton of discussions about this in the archives, probably more than you would be able to read in one night.
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